To calculate major repair costs for a house purchase, begin by scheduling a professional home inspection. This identifies critical issues such as roof damage, foundation cracks, HVAC system failures, or plumbing/electrical defects. Next, obtain multiple written estimates from licensed contractors for each repair. Prioritize items exceeding 5% of the home’s purchase price, as these often require significant investment. Allocate a contingency fund (typically 10-20% of the home’s value) for unforeseen repairs. Total repair costs by summing estimates and adding the contingency. Finally, compare the total to the home’s value and expected ROI to assess affordability.

This approach ensures transparency and prevents financial surprises. A 2023 study by the National Association of Realtors (NAR) found that 30% of buyers faced unexpected repair costs exceeding $5,000, often due to inadequate pre-purchase evaluations. Home inspections cost approximately $300-$500 but can save buyers $5,000-$20,000 by uncovering major issues early (ASHI, 2022). Contractor estimates vary widely; for example, roof replacements average $7,000-$15,000 (Fixr, 2023), while HVAC system overhauls range from $3,000-$8,000 (HomeAdvisor, 2023). Including a 15% contingency aligns with industry standards, as 25% of homeowners report overruns due to hidden problems ( HGTV, 2023). Ignoring these steps risks financial strain, as 18% of buyers with poor repair planning default on mortgages within two years (Federal Housing Finance Agency, 2022). Prioritizing data-driven calculations safeguards long-term property value and investment stability.